Acinetobacter baumannii complex

From IDWiki
Acinetobacter baumannii complex

Background

Microbiology

Antimicrobial Resistance

  • A number of mechanisms
  • Carbapenem resistance is usually mediated by acquisition of OXA-type class D carbapenemase
    • Less common mechanisms include acquisition of class B (VIM, IMP, and NDM) carbapenemases, loss of outer membrane CarO protein, and modification of AdeABC efflux pump

Management

Carbapenem-Resistant Acinetobacter baumannii

  • Infection must be distinguished from colonization of the airway or wound
  • Resistance may be mediated by a number of β-lactamases, including OXA-24/40-like carbapenemases, OCA-23-like carbapenemases, and metallo-β-lactamases, and often has sulbactam resistance
  • Often have concurrent aminoglycoside-modifying enzymes or 16S rRNA methyltransferases, which confer resistance to aminoglycosides including plazomicin
  • Single-agent treatment may be sufficient for mild infections
    • High-dose ampicillin-sulbactam is preferred, at a dose of either 9 g IV q8h infused over 4 hours, or 27 g IV q24h continuous infusion
  • Combination treatment with at least two agents that have in vitro activity for most other infections